More on hybrids

This regards the April issue letter from Richard Evans, director of American Brahman Breeders Association, on the Crossbreeding With Composites article in the February issue of BEEF. I can only say, with all due respect, that he's dead wrong in his comments regarding hybrids and heterosis. A quick look at another dictionary, such as Webster's Ninth New Collegiate Dictionary, provides this definition

May 01, 2006

This regards the April issue letter from Richard Evans, director of American Brahman Breeders Association, on the “Crossbreeding With Composites” article in the February issue of BEEF.

I can only say, with all due respect, that he's dead wrong in his comments regarding hybrids and heterosis.

A quick look at another dictionary, such as “Webster's Ninth New Collegiate Dictionary,” provides this definition of “hybrid” — the offspring of two animals or plants of different races, breeds, varieties, species or genera.

The amount of heterosis produced in a mating is dependent on the amount of heterozygosity produced, and the most heterozygosity produced (in order from most to least) would be mating:

animals of different species,

animals of different breeds,

distinctly different inbred lines of the same breed,

unrelated animals of the same breed, and

related animals of the same breed.

The designation of genus, specie or breed is a label imposed by man; heterosis is still dependent on the amount of heterozygosity produced in a mating, as heterosis is proportional to heterozygosity. For all practical purposes, mating animals of the same breed produces almost no useful heterosis.

Mating animals of different species has generally been met with major fertility problems, i.e., mules, bison x cattle crosses, yak x cattle crosses, etc. Thus, for at least the last 60 years, crossing breeds of cattle has been the predominant practice, and extensive research has repeatedly proven heterosis or hybrid vigor (performance advantage of crossbred animals over and above the average of the parental breeds used) does exist.

Furthermore, heterosis isn't only measurable in the F1 (or first cross), but also in the F2, F3, and F4 crosses. This is borne out by the Germ Plasm Utilization project at the U.S. Meat Animal Research Center, Clay Center, NE.

The fact Brahman (Bos indicus) and domestic cattle (Bos taurus) mate and produce offspring with basically no fertility loss would, in the minds of some taxonomists, indicate Bos indicus isn't a distinctly different specie from Bos taurus. Reference “Animal Breeding Plans” by Jay Lush, Iowa State University Press, 1945.

While the original article in the February issue says: “maximum heterosis is realized in the first cross of distinctly different parents,” it would have been more precise to say: “maximum heterosis is realized in the first cross of distinctly different parental breeds.”Jim Gosey Animal science professor emeritus University of Nebraska, Lincoln

Controlled burns are proven

I've spent a lifetime with livestock and row crop farming and farm-animal veterinary medicine in the coastal plain farming area of lower South Carolina. I learned early on, and it was reinforced in my veterinary practice, that luck and coincidence rarely explain things. The answer, and ultimate solution to a problem, generally lies in “cause and effect.”

Regular controlled burning used to be standard practice in our area. We rarely had catastrophic forest fires, the trees grew faster and reproduced better, and natural grasses for the cattle did better. We rarely saw a tick on livestock and very little of the tick-borne diseases and parasites.

Slowly, as the years went by, and with the crusades against controlled burning, all this changed. A coincidence? Hardly so.Earle Goodman, DVM Turbeville, SC

Thoughts on buying bulls

Buying enough bulls (“Bullish Returns, Part II,” March BEEF, page 82) to be assured of having those last few cows sought and serviced, wherever they might be, has a definite downside. Purchase price, feed — enough for at least one more cow, one more calf to sell, fighting with possible bull injuries, broken corral planks and miscellaneous annoyances, and minus the salvage value at the sales ring on several insurance bulls, all adds up.

Prices being what they are right now, those late, late calves may allow the cow to break even on her feed and pasture bill. But the time seems to be coming when it'll take the profit from another earlier-calving cow to carry her.

Those numbers hit home some time ago here. Using Baekert Gaucho Brand just-about-stretch-proof barbwire and twisted wire fence stays, I made a pasture with steel posts 60 ft. apart; and part of a second 100 ft. apart (cattle will respect the devil of out of good wire). It includes a water hole and one short stretch of creek and I use it for breeding season use only.

Toss in a second somewhat similar pasture (and some early, early crested wheatgrass acreage) and 85% of 200 cows are bred the first heat period, using five, sometimes six, bulls.